Universal moca gateway splitter

ABSTRACT

A Multimedia over Coax Alliance (MoCA) gateway splitter that includes a directional coupler (including a first transmission path and a second transmission path), a gateway port and a cable television (CATV) input port each electrically connected to the first transmission path, and a MoCA port electrically connected to the second transmission path such that the MoCA port is isolated from the CATV input port and coupled to the gateway port. Multiple MoCA ports may be electrically connected to the second transmission path (e.g., via a resistive splitter). The second transmission path may be electrically connected to ground. The MoCA gateway splitter may include multiple (e.g., two or three) gateway ports, each electrically connected to the CATV input port via a directional coupler (and, e.g., one or more hybrid splitters). In those embodiments, each directional coupler may be electrically connected to the MoCA port(s), for example, via a common microstrip node.

CROSS-REFERENCE TO RELATED APPLICATIONS

This application is a continuation of co-pending U.S. patent applicationSer. No. 16/910,800, filed Jun. 24, 2020, which claims the benefit ofpriority of PCT Application No. PCT/CN2019/115342, filed on Nov. 4,2019, and U.S. Provisional Patent Application No. 62/959,034, filed Jan.9, 2020, the content of which are relied upon and incorporated herein byreference in their entirety.

BACKGROUND

The disclosure relates generally to a gateway splitter and moreparticularly to a gateway splitter that utilizes a directional coupler.

Typical cable television (CATV) systems provide for sharing a commoncoaxial medium and permit various users in the system to communicatewith the headend of the system, where CATV signals originate, but notwith each other (due to the directionality of the signal flow imposed bythe nature of the active and passive equipment that direct signalsbetween the head end and the subscribers).

Multimedia over Coax Alliance (MoCA) systems have been developed thatoperate in a different frequency band than CATV systems. MoCA systemsare designed to communicate bilaterally with each other, meaning thatany port of a MoCA system device serves both an input and output port.MoCA devices are typically located within a home or building forpermitting users to communicate with a dedicated MoCA networking device(a gateway device) that provides functionality for each user toselectively record a television program for later viewing.

Cable gateway devices have the capability to communicate with the CATVheadend generally in the (lower) CATV frequency band and to communicatewith MoCA devices in the (higher) MoCA frequency band. Accordingly, suchcable gateway devices permit information that is transmitted through apublic CATV system to be shared amongst MoCA devices joined in a privatenetwork within a commercial or residential building. Typical gatewaydevices permit CATV signals received in the CATV frequency band to berebroadcast in the MoCA frequency band via connections controlledthrough (typically digital) logic means, completely avoiding the use ofphysical switching or movement of cables between ports.

However, it is important that MoCA systems keep the CATV input signalsisolated from the MoCA signals within the system. Conventional MoCAgateway splitters isolate CATV input signals from MoCA signals using afilter.

FIG. 1 is a diagram of a gateway splitter 100 that includes aconventional hybrid power splitter.

As shown in FIG. 1, the gateway splitter 100 includes a CATV input port110 for receiving a CATV input signal from a CATV headend, a gatewayport 120 that is connectable to a gateway device, and a number of MoCAports 180 that are each connectable to a MoCA device. The MoCA ports 180are connected via a resistive splitter 170 that includes resistors 172and a common resistive splitter node 174. The gateway port 120 isconnected to a hybrid splitter 150, which is connected to the CATV inputport 110 and the MoCA ports 180 (via the resistive splitter 170).

The gateway splitter 100 enables the gateway device connected to thegateway port 120 to function as a media server and communicate with boththe (broader) CATV network and (local) MoCA network over two separatebandwidths. The CATV network is connected to one branch of the hybridsplitter 150 and the MoCA network is connected to the other branch ofthe hybrid splitter 150. The CATV input port 110 receives the (lowerfrequency) CATV input signal from a CATV headend, which is distributedto a gateway device connected to the gateway port 120. The gatewaysplitter 100 also allows the gateway device that is connected to thegateway port 120 to bidirectionally communicate with the CATV headend inthe CATV frequency band. The gateway splitter 100 also allows thegateway device connected to the gateway port 120 to bidirectionallycommunicate with MoCA devices connected to the MoCA ports 180 in the(higher frequency) MoCA frequency band. The gateway device connected tothe gateway port 120 can then act as a server that bidirectionallycommunicates with the CATV headend in the (lower frequency) CATVfrequency band and the MoCA devices connected to the MoCA ports 180 canact as client devices that bidirectionally communicate with the gatewaydevice connected to the gateway port 120.

One benefit of the topology shown in FIG. 1 is that the gateway splitter100 is not frequency dependent, meaning each network can be anybandwidth. The disadvantage of the topology shown in FIG. 1 is the powerinefficiency because each branch of the hybrid splitter 150 has a 3-dBloss. Also, network isolation is limited to the phase cancellationacross the branches of the hybrid splitter 150, which is generallyinsufficient to meet the isolation requirements of the CATV frequencyband.

FIG. 2 is a diagram of a prior art gateway splitter 200 that includes adiplex filter.

As shown in FIG. 2, the gateway splitter 200 also includes a CATV inputport 110, a gateway port 120, and a number of MoCA ports 180 (connectedvia a resistive splitter 170 that includes resistors 172 a commonresistive splitter node 174). The gateway port 120 is connected to thecommon node of a diplex filter 250 that includes a low-pass filtersection 252 and a high-pass filter section 258. The low-pass filtersection 252 is connected to the CATV input port 110 and the high-passfilter section 258 is connected to the MoCA ports 180 via the resistivesplitter 170. The low-pass filter section 252 is tuned to allow thegateway port 120 to communicate bidirectionally with the CATV input port110 in the lower CATV frequency band. Meanwhile, the high-pass filtersection 258 is tuned to allow the gateway port 120 to communicatebidirectionally with the MoCA ports 180 in the higher MoCA frequencyband. An example of the topology shown in FIG. 2 is FIG. 8 of U.S. Pat.No. 8,752,114 to Shapson.

A benefit of the topology shown in FIG. 2 is that the CATV network iseffectively isolated from the MoCA network by the filter. Anotherbenefit is that the power is not divided between the two networksbecause the through-loss of the lower and higher frequency bands throughthe diplex filter 250 is typically less than 1 dB. The disadvantage ofthe topology shown in FIG. 2 is that the frequency band split is hardwired. If the bandwidth allocations of the CATV and MoCA networkschange, new products need to be designed, developed, and deployed to allof the residences and businesses using the prior art gateway splitters200.

Until recently, the CATV frequency band was specified as 5 to 1002 MHzand the MoCA frequency band was specified as 1125 to 1675 MHz. However,the recent Data Over Cable Service Interface Specification (DOCSIS) 3.1standard specifies a CATV frequency band of 5 to 1218 MHz and a MoCAfrequency band of 1275 to 1675 MHz. As a result, all of the existingprior art gateway splitters 200 deployed in residential and commercialbuildings will need to be replaced to comply with the new DOCSIS 3.1standard and provide interaction between DOC SIS 3.1-compliant devices.

Accordingly, there is a need for a MoCA splitter that provides a gatewayport with access to both a CATV network and a MoCA network with minimalattenuation while isolating the MoCA network from the CATV networkwithout relying on internal filters with hard-wired frequency cutoffs toisolate the MoCA network from the CATV network.

SUMMARY

An aspect of this disclosure is a “universal” Multimedia over CoaxAlliance (MoCA) gateway splitter that includes a directional coupler(including a first transmission path coupled to a second transmissionpath), a gateway port electrically connected to the first transmissionpath, a cable television (CATV) input port electrically connected to thefirst transmission path, and a MoCA port electrically connected to thesecond transmission path, which is terminated to ground so that the MoCAport is isolated from the CATV input port and coupled to the gatewayport.

In some examples, multiple MoCA ports may be electrically connected tothe second transmission path (e.g., via a resistive splitter). In someembodiments, the universal MoCA gateway splitter may include multiple(e.g., two or three) gateway ports, each electrically connected to theCATV input port via a directional coupler (and, e.g., one or more hybridsplitters). In those embodiments, the coupled line of each directionalcoupler may be electrically connected to the MoCA port(s), for example,via a common microstrip node.

Another aspect of this disclosure is a method of making a universal MoCAgateway splitter, the method including electrically connecting a gatewayport to a first transmission path of a directional coupler (having asecond transmission path that is coupled to the first transmissionpath), electrically connecting a CATV input port to the firsttransmission path, and electrically connecting a MoCA port to the secondtransmission path such that the MoCA port is isolated from the CATVinput port and coupled to the gateway port.

In some examples, the method may include electrically connectingmultiple MoCA ports to the second transmission path (e.g., via aresistive splitter). In some applications, the method may furtherinclude terminating the second transmission path. In some embodiments,the method may further include electrically connecting multiple (e.g.,two or three) gateway ports to the CATV input port, each via adirectional coupler (and, e.g., one or more hybrid splitters). In thoseembodiments, the method may further include electrically connecting eachof the directional couplers to the MoCA port(s), for example, via acommon microstrip node.

This summary is not intended to identify essential features of theclaimed subject matter, nor is it intended for use in determining thescope of the claimed subject matter. It is to be understood that boththe foregoing general description and the following detailed descriptionare exemplary and are intended to provide an overview or framework tounderstand the nature and character of the disclosure.

BRIEF DESCRIPTION OF THE FIGURES

The accompanying drawings are incorporated in and constitute a part ofthis specification. It is to be understood that the drawings illustrateonly some examples of the disclosure and other examples or combinationsof various examples that are not specifically illustrated in the figuresmay still fall within the scope of this disclosure. Examples will now bedescribed with additional detail through the use of the drawings, inwhich:

FIG. 1 is a diagram of a gateway splitter that includes a conventionalhybrid power splitter;

FIG. 2 is a diagram of a prior art gateway splitter that includes adiplex splitter;

FIG. 3 is a diagram of a universal MoCA gateway splitter that includes adirectional coupler according to an exemplary embodiment;

FIG. 4 is a cross-sectional view of a coupled microstrip transmissionlines according to an exemplary embodiment;

FIG. 5 is a top view of the coupled microstrip transmission lines ofFIG. 4 forming a directional coupler according to an exemplaryembodiment;

FIG. 6 is a diagram of a universal MoCA gateway splitter that combinesthe universal MoCA gateway splitter of FIG. 3 with the directionalcoupler of FIG. 5 according to an exemplary embodiment;

FIG. 7 is a diagram of a universal MoCA gateway splitter that providesmultiple gateway ports by connecting multiple directional couplers to acommon microstrip node according to an exemplary embodiment;

FIG. 8 is a diagram of a universal MoCA gateway splitter that providesthree gateway ports according to an exemplary embodiment;

FIG. 9 is a schematic diagram of a practical embodiment of a universalMoCA gateway splitter having three gateway ports and four MoCA ports;

FIG. 10 is a graph of the insertion loss from the CATV input to thegateway ports of a prior art MoCA diplex filter, where the specificationindicates the maximum insertion loss allowed below 1002 MHz, andindicates the minimum loss allowed above 1125 MHz;

FIG. 11 is a graph of the isolation from the gateway ports to the MoCAports of a prior art MoCA diplex filter where the specificationindicates the maximum loss allowed above 1125 MHz;

FIG. 12 is a graph of the insertion loss from the CATV input port to thegateway ports of the universal MoCA gateway splitter where thespecification indicates the maximum loss allowed below 1218 MHz;

FIG. 13 is a graph showing the isolation loss of a gateway port to aMoCA port of the universal MoCA gateway splitter where the specificationindicates the maximum isolation loss allowed above 1125 MHz;

FIG. 14 is a diagram of the universal MoCA gateway splitter with apoint-of-entry low-pass filter that may be provided between the input ofthe universal MoCA gateway splitter and the CATV headend according to anexemplary embodiment;

FIG. 15 is a graph showing the insertion loss of the universal MoCAgateway splitter from the CATV input port to the MoCA ports where thespecification indicates the minimum loss allowed below 1002 MHz;

FIG. 16 is a graph showing the insertion loss from the CATV input of thepoint-of entry filter to the gateway ports of the universal MoCA gatewaysplitter showing the effect of adding the point of entry filter to theuniversal gateway splitter loss of FIG. 12; and

FIG. 17 is a graph showing the insertion loss from the CATV input of thepoint-of entry filter to the MoCA ports of the universal MoCA gatewaysplitter showing the effect of adding the point of entry filter to theuniversal gateway splitter loss of FIG. 15.

DETAILED DESCRIPTION

In describing the illustrative, non-limiting embodiments illustrated inthe drawings, specific terminology will be resorted to for the sake ofclarity. However, the disclosure is not intended to be limited to thespecific terms so selected, and it is to be understood that eachspecific term includes all technical equivalents that operate in similarmanner to accomplish a similar purpose. Several embodiments aredescribed for illustrative purposes, it being understood that thedescription and claims are not limited to the illustrated embodimentsand other embodiments not specifically shown in the drawings may also bewithin the scope of this disclosure.

Disclosed is a universal Multimedia over Coax Alliance (MoCA) gatewaysplitter that includes a directional coupler (including a firsttransmission line and a second transmission line), a gateway portelectrically connected to the first transmission line, a cabletelevision (CATV) input port electrically connected to the firsttransmission line, and a MoCA port electrically connected to the secondtransmission line, which is terminated to ground, so that the MoCA portis isolated from the CATV input port and coupled to the gateway port. Insome examples, multiple MoCA ports may be electrically connected to thesecond transmission line (e.g., via a resistive splitter). In someembodiments, the universal MoCA gateway splitter may include multiple(e.g., two or three) gateway ports, each electrically connected to theCATV input port via a directional coupler (and, e.g., one or more hybridsplitters). In those embodiments, each directional coupler may beelectrically connected to the MoCA port(s), for example, via a commonmicrostrip node.

FIG. 3 is a diagram of a universal MoCA gateway splitter 300 accordingto an exemplary embodiment.

As shown in FIG. 3, the gateway port 120 of the universal MoCA gatewaysplitter 300 is connected to the CATV input port 110 via a directionalcoupler 350. Meanwhile, the gateway port 120 is connected to theresistive splitter 170 via the directional coupler 350 and high-passcoupling 360. As described in detail below, the universal MoCA gatewaysplitter 300 avoids the frequency dependence of built-in filters whilepreserving throughput efficiency between the CATV input port 110 and thegateway port 120 by broadly directing gateway signals in the MoCAfrequency band to the MoCA ports 180 and away from the CATV input port110.

In some embodiments, the directional coupler 350 uses coupledtransmission paths. Transmission paths are “coupled” when they arearranged in close enough proximity that energy from one path passes tothe other path. In some embodiments, the directional coupler 350 is amicrostrip directional coupler that uses coupled transmission lines. Amicrostrip directional coupler is a stable and reliable manufacturingtechnique suitable for high-volume production at low cost.

FIG. 4 is a cross-sectional view of a coupled microstrip transmissionlines 400 according to an exemplary embodiment.

As shown in FIG. 4, the coupled microstrip transmission lines 400 mayinclude a first microstrip transmission line 420 of width W patterned ona substrate 450 of height hon top of a ground plane 430. The firstmicrostrip transmission line 420 is coupled to a second microstriptransmission line 480, also of width W, which is also patterned on thesubstrate 450. In the embodiment shown, the first transmission line 420and second transmission line 480 are elongated, thin, and rectangular inshape. In addition, the first microstrip transmission line 420 and thesecond microstrip transmission line 480 each have a respectivelongitudinal axis and longitudinal sides. The longitudinal axis andsides of the first and second transmission lines 420, 480 extendsubstantially parallel to one another at the top surface of thesubstrate 450 and are separated by a distance S. While the firstmicrostrip transmission line 420 and the second microstrip transmissionline 480 can be any length, the portions of the first microstriptransmission line 420 and the second microstrip transmission line 480that are in close proximity (i.e., separated by the distance S) eachhave a length L as described below.

The simplicity of the coupled microstrip transmission lines 400 providesa number of benefits. On a conventional circuit board, the microstripdesign functions best at frequencies above 1 GHz. A high-frequencydirectional coupler can be constructed entirely within the circuit boardlayout by controlling the width W of the microstrip transmission lines420 and 480, the distance S between the microstrip transmission lines420 and 480, and the length L of the portions of the microstriptransmission lines 420 and 480 that are in close proximity.

FIG. 5 is a top view of the coupled microstrip transmission lines 400 ofFIG. 4 forming a directional coupler 500 according to an exemplaryembodiment.

As shown in FIG. 5, the directional coupler 500 includes an input port520 and an output port 510 at opposing transverse ends of the firstmicrostrip transmission line 420 and a tap port 580 and an isolated port530 at opposing transverse ends of the second microstrip transmissionline 480. The tap port 580 of the second microstrip transmission line480 is proximate (i.e., separated by the distance S) the input port 520of the first microstrip transmission line 420. The isolated port 530 isproximate (i.e., separated by the distance S) the output port 510 of thefirst microstrip transmission line 420.

Microstrip couplers (like the directional coupler 500) function as“reverse” couplers. Energy propagating in a wave on the first microstriptransmission line 420 excites a wave in the adjacent second microstriptransmission line 480 that is coupled to the first microstriptransmission line 420 by the electromagnetic energy induced in theshared dielectric medium between them. Energy propagating from the inputport 520 to the output port 510 on the first transmission line 420excites a wave in the opposite direction (i.e., to the tap port 580).The first microstrip transmission line 420 provides the input port 520with a direct electrical connection to the output port 510. Thedirectional propagation of energy along the first microstriptransmission line 429 of the directional coupler 500 couples the tapport 580 to the input port 520 and isolates the tap port 580 from theoutput port 510. The isolated port 530 of the directional coupler 500 isterminated (with a resistor and parallel capacitor as described below)so that signal currents to and from the tap port 580 are generatedthrough the coupling of the two microstrip transmission lines 420 and480.

The gateway port 120 is electrically connected to the input port 520(e.g., by a coaxial cable or other line). The CATV input port 110 iselectrically connected to the output port 510 (e.g., by a coaxial cableor other line). And the MoCA ports 180 are connected (via the resistivesplitter 170 and the high pass coupling 360) to the tap port 580 (e.g.,by coaxial cables or other lines). The first microstrip transmissionline 420 provides the gateway device (connected to the input port 520)with a direct and efficient connection to the CATV network (connected tothe output port 510). The directivity of the directional coupler 500couples the MoCA devices (connected to the tap port 580) to the gatewaydevice (connected to the input port 520) and isolates the MoCA devices(connected to the tap port 580) from the CATV network (connected to theoutput port 510).

As shown in FIG. 5, the first microstrip transmission line 420 providesa direct bidirectional signal path for CATV signals (I_(CATV)) betweenthe CATV input port 110 (via the output port 510) and the gateway port120 (via the input port 520). Meanwhile, as described above, thedirectional coupler 500 couples the tap port 580 to the input port 520,providing an efficient, bidirectional signal path for MoCA signals(I_(MoCA)) between the gateway port 120 (via the input port 520) and theMoCA ports 180 (via the tap port 580).

One of the characteristics of the directional coupler 500 is that thesecond microstrip transmission line 480 only couples to the firstmicrostrip transmission line 420 at frequencies approaching 1 GHz with abandpass type of response. The bandpass is designed according to the ¼wavelength of the center frequency of the passband. In the case of theMoCA frequency band, the center frequency between 1125 and 1675 MHz is1400 MHz. The wavelength of 1400 MHz on FR4 type printed circuit boardmaterial is about 100 millimeters. Therefore, the directional coupler500 may be created by printing microstrip transmission lines 420 and 480that travel in close proximity (i.e., separated by the distance S) for adistance L of 25 millimeters, which is approximately ¼ of the wavelengthof the center frequency of the MoCA frequency band. Therefore, thedirectional coupler 500 directs signals in the MoCA frequency bandbetween the MoCA ports 180 and the gateway port 120 instead of to theCATV system at the CATV input port 110. Meanwhile, the frequencyresponse of the tap port 580 drops off above and below the centerfrequency of the passband (in this instance, the MoCA frequency band).Therefore, the directional coupler 500 does not divert significant powerin the CATV frequency band from the through path along the firsttransmission line 420, optimizing the throughput of CATV signals betweenthe CATV input port 110 and the gateway port 120. The directionalcoupler 500 allows the universal MoCA gateway splitter 300 toaccommodate different band-split frequency allocations (e.g., 1 GHz and1.2 GHz, which are typical of current CATV distribution systems). Thedirectional coupler 500 also eliminates the need for the universal MoCAgateway splitter 300 to include filters (like the low-pass filtersection 252 and high-pass filter section 258 of the prior art gatewaysplitter 200) by isolated the CATV input port 110 from the MoCA ports180 using only the bandwidth limitations and directivity of thedirectional coupler 500.

In the embodiment shown in FIGS. 4-5, the coupling efficiency iscontrolled primarily by designating the spacing between the coupledmicrostrip transmission lines 420 and 480. Referring back to FIGS. 4 and5, the coupling and the bandwidth of the directional coupler 500 aredetermined by the length L of the microstrip transmission lines 420 and480, which may be equal to ¼ of the wavelength of the median frequencyof the MoCA frequency band, the width W of the microstrip transmissionlines 420 and 480, which determines the characteristic impedance of themicrostrip transmission lines 420 and 480, and the distance S of themicrostrip transmission lines 420 and 480, which determines the degreeof coupling between the microstrip transmission lines 420 and 480.However, there are several methods of arranging the coupled lines Oneexample is the Lange Interdigitated Strip Line coupler (see U.S. Pat.No. 3,516,024, which is hereby incorporated by reference). The coupledbandwidth can be extended by adding more coupled sections as is done inhigher order discrete-component band pass filters.

FIG. 6 is a diagram of a universal MoCA gateway splitter 600, whichcombines the universal MoCA gateway splitter 300 of FIG. 3 with thedirectional coupler 500 of FIG. 5 according to an exemplary embodiment.

As shown in FIG. 6 and described above, the CATV input port 110 iselectrically connected to the output port 510 of the first microstriptransmission line 420 of the directional coupler 500, the gateway port120 is electrically connected to the input port 520 of the firstmicrostrip transmission line 420 of the directional coupler 500, theMoCA ports 180 are connected (via the resistive splitter 170) to the tapport 580 of the second microstrip transmission line 480 of thedirectional coupler 500, and the isolated port 530 of the directionalcoupler 500 is terminated with a resistor 682 and parallel capacitor 684so that signal currents to and from the tap port 580 are generatedthrough the coupling of the two microstrip transmission lines 420 and480. The tap port 580 may be electrically connected to the resistivesplitter 170 via high-pass coupling 360. As described below, each of theresistors 172 in the resistive splitter 170 has a resistance Rs, thetermination resistor 682 has a termination resistance Rt and thecapacitor 684 has a termination capacitance Ct.

In some embodiments, it may be beneficial to provide multiple gatewayports 120 to accommodate multiple gateway devices. Prior art MoCAsplitters provide multiple gateway or modem ports by using a hybridsplitter to connect those gateway/modem ports to a common node (e.g.,the common node of a diplex filter). Hybrid splitters are necessary toprovide bidirectional signal connectivity between multiple gateway portsand the CATV input port since CATV band frequencies extend from 1 GHz toas low as 5 MHz. However, as described above, a hybrid splitterintroduces power inefficiency as each branch of the hybrid splitter hasa 3-dB loss. This is unavoidable when splitting the total power of theCATV bandwidth between the CATV input port and multiple gateway ports.Accordingly, there is a need to provide a MoCA gateway splitter havingmultiple gateway ports 120 without introducing hybrid splitter lossesbetween the gateway ports 120 and the MoCA ports 180.

FIG. 7 is a diagram of a universal MoCA gateway splitter 700 thatprovides multiple gateway ports 120 by connecting multiple directionalcouplers 500 between each gateway port 120 and a common microstrip node780 according to an exemplary embodiment.

As shown in FIG. 7, the universal MoCA gateway splitter 700 includes afirst gateway port 120 a that is connected to the CATV input port 110via a first microstrip transmission line 420 a of a first directionalcoupler 500 a. The first microstrip transmission line 420 a of the firstdirectional coupler 500 a provides a direct and efficient connectionbetween a first gateway device (connected to the first gateway port 120a) and the CATV network (connected to the CATV input port 110) asdescribed above. The first directional coupler 500 a also includes asecond microstrip transmission line 480 a, which directs MoCA frequencyband signals to and from the first gateway port 120 a to a commonmicrostrip node 780, which is electrically connected to the MoCA ports180 via the resistive splitter 170 (as described above with reference toFIGS. 3 and 6). The second microstrip transmission line 480 a of thefirst directional coupler 500 a is terminated with a resistor 682 andparallel capacitor 684 (as shown and described above with reference toFIG. 6).

The universal MoCA gateway splitter 700 also includes a second gatewayport 120 b that is connected to the CATV input port 110 via a firstmicrostrip transmission line 420 b of a second directional coupler 500b. Again, the first microstrip transmission line 420 b of the seconddirectional coupler 500 b provides a direct and efficient connectionbetween a second gateway device (connected to the second gateway port120 b) with the CATV network (connected to the CATV input port 110). Thesecond directional coupler 500 b also includes a second microstriptransmission line 480 b, which directs MoCA frequency band signals toand from the second gateway port 120 b to the MoCA ports 180 via thecommon microstrip node 780. While not labeled in FIG. 7, the secondmicrostrip transmission line 480 b of the first directional coupler 500b is also terminated with a resistor 682 and parallel capacitor 684 (asshown and described above with reference to FIG. 6).

The CATV input port 110 may be electrically connected to the firstmicrostrip transmission lines 420 a and 420 b of both directionalcouplers 500 a and 500 b via a hybrid splitter 710. While each branch ofthe hybrid splitter 710 has a 3-dB loss in the CATV frequency band, thisloss increases as frequencies extend into the MoCA frequency band.Therefore, while it might seem advantageous to place a singledirectional coupler between the CATV input port 110 and the input of thehybrid splitter network 710 serving the gateway ports 120, MoCA signalsoriginating from the gateway ports 120 and bound for the MoCA ports 180would be attenuated by the inefficiency of the hybrid splitters 710 atthese frequencies. The connection between the outputs of the hybridsplitter 710 and the gateway ports 120 of the universal MoCA gatewaysplitter 700, by contrast, are transmission lines that can couple theMoCA signals more directly by coupling each line 480 to a common node780 connected to the input of the MoCA splitter 170.

As more gateway ports 120 are added to support more gateway devices,each gateway port 120 is coupled (via a directional coupler 500) to thecommon microstrip node 780. Since directional couplers 500 function inthe MoCA frequency band, the common microstrip node 780 serves to reducethe natural port-to-port isolation characteristic of hybrid splitters710 above the CATV frequency band by providing a high-frequency shuntpath across the outputs of the hybrid splitter 710. This is arequirement common to MoCA networks, where each MoCA port 180 is able tocommunicate bilaterally with any other MoCA port 180 and any gatewayport 120.

The resistors 172 situated between the MoCA ports 180 and the commonresistive splitter node 174 determine the insertion loss from any MoCAport 180 to any other MoCA port 180 are calculated to ensure that eachMoCA port 180 has a 75-ohm impedance when terminated with 75 ohms. Thetermination resistance Rt of the coupled second microstrip transmissionlines 480 a and 480 b, when combined in parallel, may be equivalent tothe resistance Rs of the resistors 172 in the resistive splitter 170.

The example resistive splitter 170 shown in FIG. 7 is a 5-port resistivesplitter. In order to achieve 75-ohm impedance at every port and equalinsertion loss to each port, the resistance Rs of each resistor 172connected to each MoCA port 180 may be 50 ohms, yielding an insertionloss of 14 dB from one MoCA port 180 to another. The terminationresistance Rt of the coupled second microstrip transmission lines 480 aand 480 b may be calculated to be 100 ohms (to equal the 50-ohm sourceimpedance of the other ports). In practice, however, lower insertionloss is favored over 75-ohm impedance in the MoCA frequency band.Therefore, the resistance Rs of the resistors 172 may be 33 ohms.Similarly, the termination resistance Rt of the coupled secondmicrostrip transmission lines 480 a and 480 b influences the insertionloss between the gateway ports 120 and the MoCA ports 180. In practice,impedance match at the MoCA ports 180 is traded-off for lower insertionloss, so the resistance Rt of each of the second microstrip transmissionlines 480 a and 480 b may be 43 ohms and the termination capacitance Ct(as shown in FIG. 6) may be 1.2 picofarads in parallel to emphasize thehigher frequencies, which are affected more by printed circuit losses.

The common microstrip node 780 is coupled to the common resistivesplitter node 174 through a small capacitor that operates as a high passcoupler 360 that serves to limit the lower end of the MoCA passband. Itfurther limits the lower frequency of the effective band-passcharacteristic of the directional coupler to meet the CATV-to-MoCAinsertion loss specifications in the CATV frequency band. Thecapacitance value of the capacitor 360 in this example may be 1.3picofarads. Two capacitors in series may be used to achieve the preciseamount of roll-off at the lower end of the MoCA frequency band. Aprinted capacitor is another alternative to reduce components withconsistent results.

FIG. 8 is a diagram of a universal MoCA gateway splitter 800 thatprovides three gateway ports 120 according to an exemplary embodiment.

As shown in FIG. 8, the universal MoCA gateway splitter 800 includes afirst gateway port 120 a electrically connected to the CATV input port110 via a first microstrip transmission line 420 a of a firstdirectional coupler 500 a (and a hybrid splitter 710 a), a secondgateway port 120 b electrically connected to the CATV input port 110 viaa first microstrip transmission line 420 b of a second directionalcoupler 500 b (and hybrid splitters 710 a and 71 b), and a third gatewayport 120 c electrically connected to the CATV input port 110 via a firstmicrostrip transmission line 420 c of a third directional coupler 500 c(and the hybrid splitters 710 a and 71 b). Each of the three directionalcouplers 400 a-c also include a second transmission line 480 a-celectrically connected to the MoCA ports 180 via a common microstripnode 780.

By combining all of the MoCA frequency band signals from the gatewayports 120 at a single microstrip node 780, the number of splitter portsis minimized, which yields the lowest attenuation from each MoCA port180 to another MoCA port 180. The number of MoCA ports 180 provided bythe universal MoCA gateway splitter 800 can be increased (e.g., to 6 or8) by connecting each of the MoCA ports 180 to the common resistivesplitter node 174 and adjusting the resistance Rs of the resistors 172.If eight MoCA ports 180 are provided, for example, the resistivesplitter 170 would include nine branches. Rs may then be calculated tobe 60 ohms and Rt of the resistors terminating the second microstriptransmission lines 480 a-b may then be calculated to be 180 ohms. Inpractice, Rt will be chosen empirically to meet the specification forattenuation from the gateway ports 120 to the MoCA ports 180 and theresistance Rs of the resistors 172 will be chosen to reduce the lossbetween MoCA ports 180. For example, a typical industry specificationfor port-to-port loss in the MoCA frequency band is as follows:

MoCA Band Maximum Output Port to Output Port Isolation, 1125-1675 MHZMUST not exceed the following values: Access Network Port to 7-way,Access Network Port to Home Home Network Port or Network Port isolation≤28 dB Home Network Port to 7-way, Home Network Port to Home HomeNetwork Port Network isolation ≤16 dB isolation 11-way, Access NetworkPort to Home Network isolation ≤31 dB 11-way, Home Network Port to HomeNetwork isolation ≤22 dBThis example specification designates a device with 4 MoCA ports and 3Gateway ports as a 7-way device. Similarly, 8 MoCA ports and 3 Gatewayports is an 11-way device.

FIG. 9 is a schematic diagram of a practical embodiment of a universalMoCA gateway splitter 900 having three gateway ports 120 and four MoCAports 180.

Like the MoCA gateway splitter 800, the universal MoCA gateway splitter900 includes a CATV input port 110 electrically connected to a firstgateway port 120 a (via a hybrid splitter 710 a), a second gateway port120 b (via the hybrid splitter 710 a and another hybrid splitter 710 b),and a third gateway port 120 c (via the hybrid splitters 710 a and 710b). The universal MoCA gateway splitter 900 also includes MoCA ports 180electrically connected to a common microstrip note 780 via resistivesplitter 170 that includes resistors 172 and a common restive splitternode 174.

Like the MoCA gateway splitter 800, the CATV input port 110 of theuniversal MoCA gateway splitter 900 is electrically connected to thefirst gateway port 120 a via a first microstrip transmission line 420 aof a first directional coupler 500 a, to the second gateway port 120 bvia a first microstrip transmission line 420 b of a second directionalcoupler 500 b, and to the third gateway port 120 c via a firstmicrostrip transmission line 420 c of a third directional coupler 500 c.The first directional coupler 500 a includes a second microstriptransmission line 480 a in close proximity to (e.g., separated by adistance S of 0.25 millimeters) and coupled to the first microstriptransmission line 420 a, with one port terminated with a resistor 682and a capacitor 684 in parallel and the other port electricallyconnected to the common microstrip node 780. Similarly, the seconddirectional coupler 500 b includes a second microstrip transmission line480 b, in close proximity to (e.g., separated by a distance S of 0.25millimeters) and coupled to the first microstrip transmission line 420b, with one port terminated with a resistor 682 and a capacitor 684 inparallel and the other port electrically connected to the commonmicrostrip node 780. Finally, the third directional coupler 500 c alsoincludes a second microstrip transmission line 480 c, in close proximityto (e.g., separated by a distance S of 0.25 millimeters) and coupled tothe first microstrip transmission line 420 c, with one port terminatedwith a resistor 682 and a capacitor 684 in parallel and the other portelectrically connected to the common microstrip node 780. The resistanceof each of the resistors 682 may be 43 ohms and the capacitance of eachof the capacitors 684 may be 1.2 picofarads

As shown in FIG. 9, the CATV input port 110 is electrically connected tothe first hybrid splitter 710 a via a choke 911 that shunts the directcurrent path immediately to ground for surge protection. CATV signalsabove 5 MHz can pass without attenuation from the CATV input port 110 tothe hybrid splitter 710 a through a high-pass filter consisting of thechoke 911 and a high-voltage capacitor 912. The inductance of the choke911 may be 7.5 microhenries. The capacitance of the high-voltagecapacitor 912 may be 820 picofarads.

The hybrid splitter 710 a may include a matching transformer 913 a and acenter tapped transformer 915 a. A capacitor 914 a may compensate forthe rising impedance at high frequencies due to the inductance of thepath between the two transformers 913 a and 915 a. Isolation throughphase cancellation across the outputs of the center tapped transformer915 a may be provided by a shunt path that includes a resistor 917 a andtwo inductors 916 a and 918 a at each end of the resistor 917 a. Thematching transformer 913 a may be a 2-turn to 5-turn matchingtransformer. The center tapped transformer 915 a may be 2-turn to 2-turncenter tapped transformer. Both of the transformers 913 a and 915 a maybe wound on ferrite bead cores. The capacitance of the capacitor 914 amay be 1 picofarad. The resistance of the resistor 917 a may be 200ohms. The inductance of each of the inductors 916 a and 918 a may be 5.6nanohenries.

The first output of the hybrid splitter 710 a may be electricallyconnected to the first transmission line 420 a of the first directionalcoupler 500 a via a high-voltage capacitor 922 a. A capacitor 929 a maycompensate for the rising impedance at high frequencies due to theinductance of the path from the first output of the hybrid splitter 710a to the high-voltage capacitor 922 a. The capacitance of thehigh-voltage capacitor 922 a may be 2.2 nanofarads. The capacitance ofthe capacitor 929 a may be 0.75 picofarads.

The second hybrid splitter 710 b may also include a matching transformer913 b and a center tapped transformer 915 b. Again, a capacitor 914 bmay compensate for the rising impedance at high frequencies due to theinductance of the path between the two transformers 913 b and 915 b. Andisolation through phase cancellation across the outputs of the centertapped transformer 915 b may be provided by a shunt path that includes aresistor 917 b and two inductors 916 b and 918 b at each end of theresistor 917 b. The matching transformer 913 b may be a 2-turn to 5-turnmatching transformer. The center tapped transformer 915 b may be 2-turnto 2-turn center tapped transformer. Both of the transformers 913 b and915 b may be wound on ferrite bead cores. In this instance, thecapacitance of the capacitor 914 b may be 0.2 picofarads, the resistanceof the resistor 917 b may be 167 ohms, and the inductance of each of theinductors 916 b and 918 b may be 3.9 nanohenries.

The first output of the second hybrid splitter 710 b may be electricallyconnected to the first transmission line 420 b of the second directionalcoupler 500 b via a high-voltage capacitor 922 b. A capacitor 929 b maycompensate for the rising impedance at high frequencies due to theinductance of the path from the first output of the hybrid splitter 710b to the high-voltage capacitor 922 b. The capacitance of thehigh-voltage capacitor 922 b may be 2.2 nanofarads. In this instance,the capacitance of the capacitor 929 b may be 0.3 picofarads.

The second output of the second hybrid splitter 710 b may beelectrically connected to the first transmission line 420 c of the thirddirectional coupler 500 c via a high-voltage capacitor 922 c. Acapacitor 929 c may compensate for the rising impedance at highfrequencies due to the inductance of the path from the second output ofthe hybrid splitter 710 b to the high-voltage capacitor 922 c. Thecapacitance of the high-voltage capacitor 922 c may be 2.2 nanofaradsand the capacitance of the capacitor 929 c may be 0.3 picofarads.

The common microstrip node 780 may be electrically connected to thecommon resistive splitter node 174 via high-pass coupling 360. Thehigh-pass coupling 360 may include a capacitor 962 and a capacitor 964.The capacitance of the capacitor 962 may be 1.5 picofarads and thecapacitance of the capacitor 964 may be 12 picofarads. Alternatively,the equivalent capacitance of the two capacitors 962 and 964 in seriesmay be realized in the circuit board layout by printing two pads coupledby the dielectric of the printed circuit board substrate.

Each of the four MoCA ports 180 may be connected to the common resistivesplitter node 174 through a high-voltage capacitor 982 in series withthe resistor 172. An inductor 984 may be connected from each MoCA port180 to ground for surge protection. Each capacitor 982 may be 1nanofarad. Each resistor 172 may be 33 ohms. And each inductor 984 maybe a 7.5-turn air-core inductor.

While the gateway splitters 600-900 are described above as including themicrostrip directional coupler 500 with coupled microstrip transmissionlines 400, one of ordinary skill in the art would recognize the gatewaysplitter 300 may instead include another type of directional coupler(e.g., a strip line coupler, a coaxial coupler, or a hybrid transformerdirectional couplers). Features identified above with reference to eachembodiment may then be combined to provide any of the specific benefitsdescribed in this disclosure or otherwise known in the art.

Problems Identified in the Prior Art

Since the bandwidth of the CATV system is still expanding, the objectiveof the CATV system operator is to be able to use this device in varioussystems whether they have an upper CATV bandwidth of 1002 MHz and alower MoCA bandwidth of 1125 MHz or, alternatively, for more advancedbandwidth structures that typically have an upper CATV bandwidth of 1218MHz and a lower MoCA bandwidth of 1275 MHz.

It has been common practice, as witnessed by the prior art gatewaysplitter 200 shown in FIG. 2, to filter the path from the CATV inputport 110 to the gateway port 120 with a low-pass filter designed to passthe CATV bandwidth and reject the MoCA bandwidth. This was done byconnecting the CATV input port 110 to either the low-pass section 252 ofa diplex filter 250 as shown in FIG. 2 or to a discrete low-pass filterto block MoCA signals from returning to the CATV input port 110 from thegateway port 120 or the MoCA ports 180. Since the gateway devicecommunicates with both the CATV network and the MoCA network, thegateway port 120 will pass signals from 5 MHz to 1675 MHz. This meansthat MoCA frequency band signals originating from the gateway devicewould communicate with both the CATV network and the MoCA network unlessthey were blocked from exiting the input port. The choice of a low-passfilter or diplex filter 250 depended upon the bandwidth allocation ofthe CATV network and was determined by electronic components.

FIG. 10 is a graph of the insertion loss from the CATV input port 110 tothe gateway ports 120 (or “access network” ports) of a prior art MoCAdiplex filter (designed for a 1002 MHz CATV system) where thespecification indicates the maximum insertion loss allowed below 1002MHz and the minimum loss allowed above 1125 MHz. Three traces arevisible indicating that there are three gateway ports 120 connected tothe outputs of an unbalanced 3-way splitter. The sharp cut-off above1002 MHz, due to the multi-stage low-pass filter section, shows thatthis product can only be used in a 1 GHz system.

FIG. 11 is a graph of the signal loss (isolation) from the gateway ports120 (or “access network” ports) to the MoCA ports 180 (or “home network”ports) of a prior art MoCA diplex filter where the specificationindicates the maximum loss allowed above 1125 MHz. As shown in FIG. 11,the diplex filter with typical multi-stage high-pass filtering has asharp roll-off as is designed for a tight band split between the CATVand MoCA frequency bands. For example, the DOCSIS 3.1 standard specifiesa CATV frequency band of 5-1218 MHz and a MoCA frequency band of1275-1675 MHz. The guard band between the low-pass section and high-passsection is only 57 MHz wide, with a stop-band attenuation specificationof greater than 40 dB. This is an aggressive cross-over requirement thatrequires careful tuning.

Benefits of the Present Disclosure

The present disclosure is referred to as a “universal” MoCA gatewaysplitter because it addresses the frequency inflexibility of the priorart MoCA splitters by removing the low-pass filter following the CATVinput port 110. FIG. 12 is a graph of the insertion loss from the CATVinput port 110 to the gateway ports 120 (or “access network” ports) ofthe universal MoCA gateway splitter 900 where the specificationindicates the maximum loss allowed below 1218 MHz. As shown in FIG. 12,the universal MoCA gateway splitter 900 is capable of efficientlytransmitting the CATV input signal from the CATV input port 110 to theone or more gateway ports 120 regardless of where the upper frequencylimit of the CATV frequency band is now or is proscribed to be in thefuture. In other words, universal MoCA gateway splitter 900 is agnosticto the bandwidth allocations of the CATV system and insertion loss fromthe CATV input port 110 to the gateway ports 120 is optimized for themost efficient transmission of signals between the CATV network and thegateway devices. Because the design objective of blocking the MoCAfrequency band with a low-pass filter has been abandoned, the CATVnetwork bandwidth can grow without equipment obsolescence.

Rather than using low-pass filtering, the universal MoCA gatewaysplitter 900 addresses access to the lowest edge of the MoCA frequencyband (which, for pre-DOCSIS 3.1 devices is 1125 MHz) through the use ofa microstrip directional coupler with ¼ wavelength tuning and capacitivecoupling. FIG. 13 is a graph showing the isolation loss from a gatewayport 120 (or “access network” port) to a MoCA port 180 (or “homenetwork” port) of the universal MoCA gateway splitter 900 where thespecification indicates the maximum isolation loss allowed above 1125MHz. As shown in FIG. 13, the smooth roll-off toward the lowerfrequencies provided by the universal MoCA gateway splitter 900 providesgentle high-pass coupling with fewer components and less precise tuning.Again, the objective of blocking the CATV frequency band from the MoCAfrequency band with a sharp high-pass filter has been abandoned.

MoCA frequency band signals can interfere with the CATV network if theyare allowed to enter or exit a network interface device through the CATVinput port 110. However, the universal MoCA gateway splitter 900provides a solution to this problem that is more cost effective toimplement than prior art MoCA splitters.

FIG. 14 is a diagram of the universal MoCA gateway splitter 900 with apoint-of-entry low-pass filter 1400 that may be provided between theCATV input port 110 of the universal MoCA gateway splitter 900 and theCATV headend 1401 according to an exemplary embodiment. A point-of-entrylow-pass filter 1400 has a cutoff frequency appropriate to the currentCATV frequency band. As the CATV frequency band expands (e.g., to 1.8GHz and beyond), the universal MoCA gateway splitter 900 will be able toadapt simply by changing the point-of-entry filter 1500 in front of it.A point-of-entry filter 1500 is a two-port device that requires verylittle effort to change in the field. A gateway splitter, on the otherhand, is an eight- to twelve-port device and changing that many coaxialconnections is more expensive from an operations and obsolescence pointof view.

FIG. 12 (described above) is a graph showing the insertion loss of theuniversal MoCA gateway splitter 900 from the CATV input port 110 to thegateway ports 120 (“access network” ports). FIG. 15 is a graph showingthe insertion loss of the universal MoCA gateway splitter 900 from theCATV input port 110 to the MoCA ports 180 (“home network” ports) wherethe specification indicates the minimum loss allowed below 1002 MHz.

FIGS. 16 and 17 are graphs showing the insertion loss of a universalMoCA gateway splitter 900 with a point-of entry filter 1400 (in thisexample, with a cutoff frequency of 1 GHz) externally connected to theCATV input port 110 as shown in FIG. 14. FIG. 16 is a graph showing theinsertion loss from the CATV input of the point-of entry filter 1400 tothe gateway ports 120 (“access network” ports) of the universal MoCAgateway splitter 900 showing the effect of adding the point of entryfilter to the universal gateway splitter loss of FIG. 12. FIG. 17 is agraph showing the insertion loss from the CATV input of the point-ofentry filter 1400 to the MoCA ports 180 (“home network” ports) of theuniversal MoCA gateway splitter 900 showing the effect of adding thepoint of entry filter to the universal gateway splitter loss of FIG. 15.

In contrast to the graph shown in FIGS. 12 and 15, FIGS. 16 and 17 showthat the universal MoCA gateway splitter 900 with the point-of entryfilter 1400 blocks MoCA frequency band signals from the gateway ports120 and MoCA ports 180 from entering the CATV network via the CATVheadend 1401. As the CATV frequency band expands, the 1 GHz point-ofentry filter 1400 may be easily replaced with a 1.2 GHz point-of-entryfilter 1400, which would extend the roll-off to 1.2 GHz. Accordingly,the universal MoCA gateway splitter 900 is easily adapted to thecharacteristic bandwidth plan of any CATV system.

As mentioned above, the gateway splitter 300 may include any type ofdirectional coupler, such as a hybrid transformer directional couplerwith wires twisted together that form coupled transmission paths. Themicrostrip directional coupler 500 of FIG. 5 with the coupled microstriptransmission lines 400 of FIG. 4, however, provides specific technicalbenefits. The microstrip directional coupler 500 of FIG. 5 does notfunction well in the CATV frequency band, which is beneficial as itprovides isolation between the CATV frequency band and the MoCAfrequency band. The first transmission line 420 has a wider bandwidththan the coupled second microstrip transmission line 480, allowingsignals in the CATV frequency band (I_(CATV)) to travel easily on thefirst transmission line 420 that connects the CATV input port 110 to thegateway port 120. The ¼ wave bandpass coupling of the coupled secondmicrostrip transmission line 480 and the directivity of the signal flowbetween the gateway port 120 and the MoCA ports 180 enhances isolationbetween the MoCA ports 180 and the CATV input 110 (as described abovewith reference to FIGS. 4-5).

The foregoing description and drawings should be considered asillustrative only of the principles of the disclosure, which may beconfigured in a variety of shapes and sizes and is not intended to belimited by the embodiment herein described. Numerous applications of thedisclosure will readily occur to those skilled in the art. Therefore, itis not desired to limit the disclosure to the specific examplesdisclosed or the exact construction and operation shown and described.Rather, all suitable modifications and equivalents may be resorted to,falling within the scope of the disclosure.

1-20. (canceled)
 21. A Multimedia over Coax Alliance (MoCA) gatewaysplitter, comprising: a directional coupler comprising: a firsttransmission path that includes an input port and an output port; and asecond transmission path, coupled to the first transmission path, thatincludes tap port and a grounded isolated port, wherein the tap port ofthe second transmission path is proximate the input port of the firsttransmission path and the isolated port of the second transmission pathis proximate the output port of the first transmission path; a gatewayport electrically connected to the input port of the first transmissionpath; a cable television (CATV) input port electrically connected to theoutput port of the first transmission path; and a MoCA port electricallyconnected to the tap port of the second transmission path such that theMoCA port is isolated from the CATV input port and coupled to thegateway port.
 22. The MoCA gateway splitter of claim 21, wherein theCATV input port is electrically connected to the output port of thefirst transmission path via a surge protection device.
 23. The MoCAgateway splitter of claim 22, wherein the surge protection device is achoke electrically connecting the CATV input port to ground.
 24. TheMoCA gateway splitter of claim 23, wherein the choke is electricallyconnected to the output port of the first transmission path via acapacitor, the choke and the capacitor forming a high-pass filter thatallows CATV signals received via the CATV input port to pass to theoutput port of the first transmission path.
 25. The MoCA gatewaysplitter of claim 21, further comprising: a MoCA splitter electricallyconnecting the MoCA port to the tap port of the second transmissionpath; one or more additional MoCA ports electrically connected to theMoCA splitter.
 26. The MoCA gateway splitter of claim 25, wherein eachof the MoCA port and the one or more additional MoCA ports areelectrically connected to the MoCA splitter via a surge protectiondevice.
 27. The MoCA gateway splitter of claim 26, wherein the surgeprotection device is an inductor electrically connecting the MoCA portor one of the one or more additional MoCA ports to ground.
 28. The MoCAgateway splitter of claim 21, further comprising: a CATV splitterelectrically connecting the CATV input port to the output port of thefirst transmission path; and one or more additional directionalcouplers, each additional coupler comprising: a first transmission pathelectrically connecting an additional gateway port to the CATV inputport via the CATV splitter; and a second transmission path, coupled tothe first transmission path, electrically connected to the MoCA port.29. The MoCA gateway splitter of claim 28, wherein the directionalcoupler and each additional directional coupler are each electricallyconnected to the CATV splitter via a capacitor.
 30. The MoCA gatewaysplitter of claim 21, wherein: the directional coupler providesfunctionality for a MoCA device to transmit signals to the gateway portover a MoCA frequency band having a center frequency, the centerfrequency having a wavelength; and the first transmission path and thesecond transmission path both have a length that is one-fourth of thewavelength of the center frequency of the MoCA frequency band.
 31. Amethod of making a Multimedia over Coax Alliance (MoCA) gatewaysplitter, the method comprising: electrically connecting a gateway portto an input port of a first transmission path of a directional couplerhaving a second transmission path, coupled to the first transmissionpath, that includes tap port and a grounded isolated port, the tap portof the second transmission path being proximate the input port of thefirst transmission path and the isolated port of the second transmissionpath being proximate an output port of the first transmission path;electrically connecting a cable television (CATV) input port to theoutput port of the first transmission path; and electrically connectinga MoCA port to the tap port of the second transmission path such thatthe MoCA port is isolated from the CATV input port and coupled to thegateway port.
 32. The method of claim 31, wherein the CATV input port iselectrically connected to the output port of the first transmission pathvia a surge protection device.
 33. The method of claim 32, wherein: thesurge protection device is a choke electrically connecting the CATVinput port to ground; the choke is electrically connected to the outputport of the first transmission path via a capacitor; and the choke andthe capacitor form a high-pass filter that allows CATV signals receivedvia the CATV input port to pass to the output port of the firsttransmission path.
 34. The method of claim 31, wherein the MoCA port iselectrically connected to the tap port of the second transmission pathvia a MoCA splitter electrically connected to one or more additionalMoCA ports.
 35. The method of claim 34, wherein each of the MoCA portand the one or more additional MoCA ports are electrically connected tothe MoCA splitter via a surge protection device.
 36. The method of claim35, wherein the surge protection device is an inductor electricallyconnecting the MoCA port or one of the one or more additional MoCA portsto ground.
 37. The method of claim 31, wherein the CATV input port iselectrically connected to the output port of the first transmission pathvia a CATV splitter, the method further comprising: providing one ormore additional directional couplers, each of the one or moredirectional couplers comprising a first transmission path and a secondtransmission path that is coupled to the third transmission path;electrically connecting the CATV input port to each first transmissionpath of each of the one or more directional couplers via the CATVsplitter; electrically connecting additional gateway ports to each ofthe first transmission paths of each of the one or more additionaldirectional couplers; and electrically connecting the MoCA port to eachof the second transmission paths of each of the one or more additionaldirectional couplers.
 38. The method of claim 37, wherein thedirectional coupler and each additional directional coupler are eachelectrically connected to the CATV splitter via a capacitor.
 39. Themethod of claim 31, wherein: the directional coupler providesfunctionality for a MoCA device to transmit signals to the gateway portover a MoCA frequency band having a center frequency, the centerfrequency having a wavelength; and the first transmission path and thesecond transmission path both have a length that is one-fourth of thewavelength of the center frequency of the MoCA frequency band.
 40. AMultimedia over Coax Alliance (MoCA) gateway splitter, comprising: aplurality of directional couplers, each directional coupler comprising:a first transmission path that includes an input port and an outputport; and a second transmission path, coupled to the first transmissionpath, that includes tap port and a grounded isolated port, wherein thetap port of the second transmission path is proximate the input port ofthe first transmission path and the isolated port of the secondtransmission path is proximate the output port of the first transmissionpath; a plurality of gateway ports, each gateway port electricallyconnected, via a capacitor, to the input port of the first transmissionpath of a respective directional coupler of the plurality of directionalcouplers; a cable television (CATV) input port electrically connected,via a surge protection device, to the output ports of the firsttransmission paths of each of the plurality of directional couplers; anda plurality of MoCA ports each electrically connected, via a surgeprotection device, to the tap ports of the second transmission paths ofeach of the plurality of directional couplers.